1. Field of the Invention
This invention relates to a method of making a silicone elastomer which is vulcanized at room temperature.
2. Description of the Prior Art
Silicone elastomers which cure at room temperature are broadly known and many curing systems have been proposed including those which cure upon exposure to moisture. Platinum catalyzed compositions which cure to elastomers are known in the art such as those which result from mixing a vinyl containing siloxane polymer and a silicon-bonded hydrogen atom containing silicon compound in the presence of a platinum catalyst.
It is also known that silicon compounds containing silicon-bonded hydroxyl radicals can be reacted with silicon compounds containing silicon-bonded hydrogen atoms in the presence of chloroplatinic acid. This is described by Robert L. Merker in U.S. Pat. No. 2,967,170. Merker describes cured resinous products prepared by reacting various siloxane materials.
It was found that when a hydroxylated siloxane and a hydrogen siloxane were mixed with a platinum catalyst, the resulting mixture cured very quickly and with many undesirable voids. It was thus unexpected that an elastomer essentially free of voids could be made and cured at room temperature from a hydroxylated siloxane, a hydrogen siloxane and a platinum catalyst.